1. Field of the Invention
The subject invention relates to a blood collection set having a needle cannula and a shield that can be driven forwardly to safely shield the needle cannula.
2. Description of the Related Art
A prior art blood collection set includes a small diameter needle cannula having a pointed distal end and a proximal end mounted to a thermoplastic hub. Portions of the blood collection set near the hub may be provided with a pair of flexible wings. The wings can be folded into face-to-face engagement with one another to facilitate digital manipulation of the small needle cannula. The wings then can be folded away from one another and taped into face-to-face engagement with the skin of the patient near a puncture site. The prior art blood collection set further includes a flexible plastic tube that has one end connected to the hub and an opposed end connected to a fitting. The fitting can be placed in communication with a reservoir to which collected blood may be directed.
The needle cannula of the prior art blood collection set typically is shielded prior to and after use to prevent accidental sticks. Needle shields used with prior art blood collection sets have taken many forms. Typically, a prior art blood collection set is packaged with a rigid tubular cap telescoped over the needle cannula to prevent accidental sticks prior to use. This tubular cap is removed from the needle cannula immediately prior to use of the blood collection set. Most prior art blood collection sets further include a second shield that is telescoped over the needle cannula and hub. The second shield may include at least one slot through which wings of the prior art hub may extend. Thus, the medical technician who uses the prior art blood collection set will hold the wings of the needle hub in one hand and the shield in the other hand after removing the needle cannula from the patient or blood donor. The wings then are slid proximally relative to the shield, thereby drawing the needle cannula into the shield. Some prior art shields are configured to engage the wings when the needle cannula has been shielded to make a re-exposure of the needle cannula difficult.
The digital manipulation that is required to shield the used needle cannula of a prior art blood collection set creates the potential for generating the accidental needle stick that the shield is intended to avoid. In particular, it is undesirable to rely upon a shielding that requires two hands to be moved in opposite directions in proximity to the point of a used needle cannula. Accordingly, the inventors herein have recognized the desirability of providing an automatically shieldable needle cannula for a blood collection set.
The subject invention relates to a blood collection set which comprises a needle cannula having a proximal end, a pointed distal end and a lumen extending therebetween.
The blood collection set further includes a hub that may be molded from a thermoplastic material. The hub includes opposite proximal and distal ends. The hub further includes concentric spaced apart inner and outer tubes extending between the proximal and distal ends. The inner and outer tubes are connected to one another at their respective proximal ends. However, the inner and outer tubes of the hub are not connected at the distal end. Thus, a cylindrical space extends proximally from the distal end of the hub and between the inner and outer tubes. A passage extends continuously between the proximal and distal ends of the inner tube of the hub. The distal end of the inner tube of the hub is securely mounted to the proximal end of the needle cannula. Thus the lumen through the needle cannula communicates with the passage through the inner tube of the hub.
A pair of deflectable fins projecting transversely from opposite sides of the outer tube of the hub at locations adjacent the distal end of the outer tube. The fins can be rotated toward one another about the outer tube and into a position where the rotated fins can be engaged by a thumb and forefinger for gripping and manipulating the blood collection set. At least one of the fins further includes a projection that extends at least partly across the opening between the inner and outer tubes at the distal end of the hub when the fins project transversely from the outer tube. However, rotation of the fins toward one another will cause the projection to rotate away from the opening to the cylindrical space between the inner and outer tubes.
The hub may further include a dorsal fin that projects radially outwardly from the outer tube at a location adjacent the distal end of the hub. The transverse fins can be rotated into engagement against the dorsal fin. Thus, the dorsal fin permits manipulation of the blood collection set when the transverse fins are in their unbiased condition and extending away from one another. However, the transverse fins can be rotated toward one another and into engagement with opposite surfaces of the dorsal fin. Thus, a user can simultaneously grip the transverse fins and the dorsal fin for manipulating the blood collection set. The outer tube may further include at least one locking aperture extending through the outer tube at a location near the distal end of the outer tube.
The blood collection set may further include a length of flexible tubing having opposed proximal and distal ends. The distal end of the flexible tubing may be connected to the proximal end of the hub such that the lumen through the needle cannula and the passage through the hub both communicate with the passage through the flexible tubing. The flexible tubing further includes a proximal end that may be connected to a fitting. The fitting may comprise a needle cannula that enables the blood collection set to be placed in communication with a reservoir for receiving a sample of blood. The tubing and the fitting may be of conventional design.
The blood collection set may further include a substantially rigid generally tubular safety cap mounted over the needle cannula for protection against accidental needle sticks prior to use of the blood collection set. The safety cap may include a proximal end that is frictionally engaged with the hub. The rigid tubular safety cap may be removed immediately prior to use of the blood collection set.
The blood collection set further includes a safety shield that is telescoped over at least portions of the inner tube of the hub and cannula and at least partly within the outer tube. Thus, the safety shield is movable within the cylindrical space between the inner and outer tubes of the hub from a proximal position, where the needle cannula is exposed, to a distal position, where the needle cannula is safely shielded. Biasing means are provided between the shield and the hub for urging the shield to the distal position. The biasing means may be a coil spring that surrounds a portion of the inner tube of the hub.
The projections on the transverse fins function as a retainer for releasably retaining the shield in the proximal position relative to the hub and the needle cannula and against the stored energy of the biasing means. Rotation of the transverse fins towards one another and/or toward the dorsal fin moves the projections of the transverse fins away from the opening to the cylindrical space between the inner and outer tubes of the hub. Thus, the safety shield is free to move in response to the stored energy of the biasing means. The safety shields and the hub may further include a lock for preventing complete removal of the safety shield from the hub when the transverse fins are moved into a position that permits the distal movement of the shield. The lock may further prevent a return proximal movement that could re-expose the used needle cannula.